QUIRC Status Report 2/6/96

This is a short summary of the major changes to QUIRC and the program since
the upgrade. Some of these changes were described in the last Mauna ikena
newsletter; the QUIRC manual will be updated shortly to include these changes.

Obvious changes - the array has been changed; you will not be able to use flats
or bad pixel masks from previous (pre-Feb 96) observing. The electronics have
been upgraded; the time for a single read is about 2.4 seconds. The "dummy
read" may not be necessary for broad-band imaging. Not using a dummy read
causes the first three lines of each quadrant to be slightly unstable with
respect to the rest of the array on the level of 5-10 ADU's. For narrow-band
imaging, this may be a significant effect. The conservative approach is to
use the dummy read. This will add 5 seconds overhead to each image.

The ADU scaling is different. Hard saturation occurs at 50,000 ADU's. It is
probably wise to keep the peak value in the image well below 40,000 to stay
below this limit. The scaling is now about 1.85 electrons/ADU. The plate
scale was measured to be 0.1886 arcsec/pixel at f/10, with a rotation in
the nominal position of 0.883 degrees CCW (e.g., N is rotated 0.883 deg E of
vertical when displayed in the normal way).

The motor for the second filter wheel failed in the lab so at the present time
only the original wheel is in QUIRC with 8 filters. Replacement cryogenic
motors are being procured and will be installed as soon as possible.
The current filters are:

J (1.2 um)

H (1.65 um)

K (2.2 um)

Kprime (2.15 um)

HKnotch (1.8 um)

H2BP23 (2.12 um)

2059BP30 (2.059 um)

2129BP23 (2.129 um)

The dewar now has a temperature sensor and heater. For normal operation, the
temperature controller should be used to set the detector temperature to 80.0K.
If the controller is not used, drifts can occur as the telescope is moved,
resulting in dark current instabilities in the array. The new array is not
thought to be more sensitive to these effects than the previous detector, but
some of the anomalies previously seen by observers with the original QUIRC
detector may have been due to this effect.

New qcdcom Commands:

1. du util

This command downloads the program to the utility board. Previously, we
did not use a utility board program. This program is necessary for moving
the filter wheels and pupil slide. After powering up QUIRC, the dsp program should be downloaded using the command
df quirc
and then download the utility program using
du util
in that order. Note that the df command must successfully complete before
doing the du command.

2. init

This command sets all qcdcom parameters to an initial state that will be
appropriate for taking data. This is intended for recovering after
something or someone has set the parameters to some weird state. You will
still want to adjust things, but this will get you to a condition that
will produce an image.